[1] During his student days he edited The Sheaf, the university newspaper, as well as working for the Canadian National Railway.
[1] With the popular front policy in place, Clarke and other communists joined the Co-operative Commonwealth Federation.
[1] In his later years, Clarke became a prominent leader of the Toronto west-end tenants' rights struggles.
[1][7] During the 1970s, Clarke and his wife Phyllis became leaders of a current in the CPC influenced by Eurocommunism, advocating for a more pluralist approach to socialism and criticizing what they saw as the party's sectarianism towards mass movements.
By 1979, increasingly skeptical that the CPC would be able to make the necessary changes, Clarke circulated a document influenced by socialist feminist ideas, raising the possibility of forming a new organization out of existing popular movements.